Method of and apparatus for treating fibrous materials



July 28, 1,970 P GRUNER ET AL 3,521,998

METHOD OF AND APPARATUS FOR TREATING FIBROUS MATERIALS Filed March 26,1968 2 sneers-sheet'l I INVENTORS fiava/ pw-ogh 74010 15 Zo/erlk ya l'ek July 28, 1970 GRUNER ET AL METHOD OF AND APPARATUS FOR TREATINGFIBROUS MATERIALS Filed March 26, 1968 2 Sheets-Sheet 2 United StatesPatent US. Cl. 8149.2 Claims ABSTRACT OF THE DISCLOSURE A method of andapparatus for treating fibrous materials provides an upright treatingchamber filled with fibrous material. Additional fibrous material iscontinuously added at one end of the treating chamber, and acorresponding quantity of fibrous material is continuously withdrawn atthe other end of the treating chamber so that new fibrous material addedadvances through the treating chamber from one to the other end thereof.An aerosol is introduced into the treating chamber for passage throughthe fibrous material therewithin either in concurrent flow with thefibrous material, or in counterflow thereto. At the respectivelyopposite end of the treating chamber the aerosol is withdrawn.

BACKGROUND OF THE INVENTION The present invention relates to thetreatment of fibrous materials, and more particularly to the treatmentof fibrous materials with aerosols. Still more specifically, the presentinvention relates to a method of treating fibrous materials withaerosols and to an apparatus for carrying out the method.

It is already known to treat fibrous materials, for instance textilematerials, with aerosols for various purposes. The reasons for suchtreatments are well known and need not be discussed. It suifices tostate that it is known to apply liquid aerosols to the surface of afibrous layer. However, it is necessary to attain a uniform treatment ofthe fibrous material. This, it has been found, can be obtained only byapplying the aerosol in excessive quantities to the fibrous layer andsubsequently to remove this excess on a padding or foulard machine.Fibrous layers treated in this manner were of necessity relatively thinso that this approach to the treating of fibrous materials with aerosolshas been less than satisfactory.

In another approach totreating fibrous materials with aerosols it isknown to advance the fibrous material pneumatically through the pipelinein contact with aerosol. While this has resulted in uniform separationof the aerosol onto the fibers of the fibrous material that is a uniformtreatment of the fibrous material, it has not been found feasible froman economic point of view because a predominant portion of the aerosolparticles failed to adhere to the pneumatically advanced fibrousmaterial and thus did not accomplish its intended purpose.

An additional approach which has been tried consists in the circulationof a solid dyestuif aerosol through a fluid bed of fibrous materialwhich is to be dyed by resort to the aerosol process. Again, however, ithas been found that this did not lead to a uniform and economicutilization of the aerosol. The fibrous material in a fluidizing processcannot be thoroughly and permanently enough opened, and is alwayssubject to the formation of fiber agglomerations or flocks which make auniform separation of the aerosol particles and their adherence on thefibers impossible. Furthermore, a single passage of the aerosol throughthe layer of fluidized fibrous material is capable of effecting onlypartial treatment of the fibrous material because of the aforementionedpoor separation of aerosol particles, so that this approach requiredseveral successive treatment stages in which the aerosol had to bepassed through the fluidized fibrous material in each case. Finally,another approach has been used, namely the filtration of aerosolsthrough a stationary layer of fibrous material. However, in such processit is well known that the amount of aerosol particles separated andadhered to the fibers depends on the concentration of such particles inthe respective aerosol being used for the treatment. Thus, whenfiltering a mono-dispersion aerosol through a layer of stationaryfibrous material, the concen tration particles in the aerosol shows adecreasing tendency, that is the concentration of particles decreases asthe pistons from the entry surface increases, and this decrease involvesan approximately non-linear relationship. An analogous phenomenon isobserved with respect to the concentration of aerosol particlesdeposited on the fibers. This decrease in concentration is even moreremarkable if polydispersion aerosols are used. Thus it has been foundthat a uniform distribution and adherence of aerosol particles withinthe entire stationary layer of fibrous material is practicallyimpossible.

The purpose of the present invention and the basic object of the same isto overcome the aforementioned disadvantages and to significantlyimprove the treatment of fibrous materials with aerosols.

SUMMARY OF THE INVENTION In accordance with one feature of our inventionwe provide a method of treating fibrous materials with aerosols, whichcomprises the confining of a mass of fibrous material in an enclosedspace having two opposite sides, the continuous addition of new fibrousmaterial to this mass at one side of the space and the continuouswithdralwal of fibrous material from the mass at the opposite otherside, so that the new material which is being added to the mass at theaforementioned one side will advance in this space to the other sidethereof. As this advancing of the fibrous material through the spacetakes place, we continuously provide for the passage of an aerosolthrough the mass of fibrous material in a predetermined direction tothereby effect substantially uniform distribution of the aerosolthroughout the fibrous material in the space.

Inasmuch as we advantageously add and Withdraw fibrous material atidentical rates, the fibrous material within the enclosed space willundergo uniform movement so that the mass of moving fibers constitutesin effect a filtering medium. The aerosol is either sucked or forced, orboth, through this filtering medium. In actual practice we prefer asimultaneous coaction of superatmospheric and su'batmospheric pressures,particularly if the treatment effects relatively thick layers or massesof fibrous materials. Of course, it will be obvious that variousdifferent types of fibrous materials can be treated in this manner, thatis have the aerosol particles adhere thereto during passage of theaerosol through the fibrous material. We are primarily concerned herewith textile fibers, that is fibers suitable for the manufacture oftextiles. Different natural and artificial fibers and blends thereof aresuitable for this purpose. It should be understood, however, that themethod and apparatus according to the present invention are applicableto aerosol treatment of fibers regardless of the intended use of suchfibers.

It will be clear that, inasmuch as the continuously newly added fibrousmaterial in effect continuously forms an entire new filtering layer atthe one side of the enclosed space and inasmuch as the fibers are movedthrough the enclosed space at a predetermined rate so that the newlyformed filtering layer advances successively in the direction away fromthe filter surface, that is the surface at which the aerosol is directedfor instrusion into the layer of fibrous material, it is in effect thisfilter layer within which-that is to whose fibersthe major concentrationof the incoming aerosol particles adheres. As each filter layer movesaway from the filter surface, it receives fewer and fewer aerosolparticles whereas the new filter layer, that is the filter layer whichbuilds up upstream of the one just discussed because of the addition ofnew fibrous materials, now similarly undergoes treatment with theaerosol particles. When considering constant density or porosity valueof the fibrous filtering medium, as well as a constant rate of thefiltering process, the separability of the aerosol particles-that is thedistribution and adherence of such particles within the filter layer-isproportional to the thickness of each filter layer. On the other hand,with a constant filter thickness the separability of the aerosolparticles can be increased by rendering the filtering medium denser.Thus, the desired separation of the aerosol particles on the fibers ofthe respective filter layer can be obtained by selecting a suitablethickness or density of the filtering medium, respectively. Evidently,these two parameters should be chosen so as to provide for optimumeconomy in consumption of the aerosol during a single passage of aerosolparticles through the fibrous material.

We have further found that it is possible to influence the separation ofthe aerosol particles by changing the filtration speed. With theexception of extremely low speeds, the separation of aerosol particlesis proportional to the filtration speed and the rate of separationincrease depends mostly on the size of the aerosol particles as well ason the diameter of the fibers which form the filter layer.

Finally, it should also be noted that the amount of aerosol particleswhich adhere uniformly to each of the advancing fibrous layers or filterlayers that is to the fibers which make up each such layer, can becontrolled by varying the concentration of aerosol. Obviously, if lowaerosol concentrations are used, the amount of particles adhered to thefibers within a given filter layer Will be smaller than with highlyconcentrated aerosols, and vice versa.

In accordance with our invention the aerosol is caused to penetrate themass of fibrous material either in concurrent fiow, that is in thedirection of movement of the mass of fibrous material or in counterflow,that is opposite the direction of movement of the fibrous material.Thus, the amounts of aerosol particles separated within each of theadvancing layers of fibrous material are alike.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a somewhat schematic verticalsectional view of an apparatus for the treatment of fibrous materialswith aerosols by a method employing concurrent aerosol flow; and

FIG. 2 is a view similar to FIG. 1, but illustrating the apparatusemploying countercurrent flow of the aerosol.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing indetail, and firstly FIG. 1 thereof, it will be seen that referencenumeral 1 identifies a substantially vertical chamber which isadvantageously of hollow cylindrical configuration. In the upper section2 of this chamber, there is arranged a fiber feed mechanism 3 whereas inthe lower section 4, which is of somewhat flared cross-section there isprovided a fiber removal mechanism 5.

The feed mechanism 3 for the addition of fibrous material comprises aknurled feed roller 6 with a feed table 7 attached thereto. Afiber-opening roller 8 is provided with a saw-tooth type cover 9 whoseteeth when they engage the fibrous material, effect opening orseparation of the fibers. The feed roller 6 is rotated via atransmission element 10 by a suitable electric motor 11; thefiber-opening roller 8 is similarly operated by an electric motor 13 viathe transmission element 12. The direction of rotation of feed roller 6is indicated by the arrow S1 and that of the fiber-opening roller 8 isindicated by the arrow S2.

The fiber-removing or withdrawing mechanism 5 provided in the section 4of the chamber 1 comprises a knurled roller 14 which cooperates with asuction-type screen cage 15 attached thereto. The cage 15 will bedescribed in more detail but at this point it is sufficient to statethat the cage 15 is coupled with the roller 14 via a transmissionelement 16, and via an additional transmission element 17 with anelectric motor 18. Thus, the roller 14 and the cage 15 are rotated asindicated by the arrows S3 and S4, respectively.

The section 4 of the chamber 1 narrows to an outlet opening 19 below thefiber withdrawing mechanism 5, and this outlet 19 communicates with ahopper-type feeder 20 of a pneumatic delivery tube 21 which lattercommunicates with a fan 22 whose operation efiects in the tube 21 astream of moving air, that is a condition of superatmospheric pressurewhich suffices for conveying fibers entering into the tube 21, throughthe hopper 20 and for advancing these fibers in the tube 21 in thedirection of the arrow S5. Fan 22 is driven via a transmission element33 by an electric motor 24, as clearly shown.

Returning now to the suction-type screen cage, it is pointed out thatthis is provided with internal stationary baflle 25, as also clearlyshown in the drawing, The screen cage is of course of known constructionand is located oppositely and in parallelism with the roller 14. Theinterior of the screen cage 15 communicates via a conduit 26 with thefan 27, the latter being driven by means of a transmission element 28from an electric motor 29. The purpose of the screen cage 15 is toaspirate or withdraw aerosol from the interior of the chamber 1.

An aerosol inlet means 30 is provided in the region of the upper section2 of the chamber 1 and in this instance consists of a tubular ringhaving jets 31 through which aerosol can issue. The ring communicatesvia a conduit 32 with the fan 27. Arranged within the conduit 32upstream of the ring, that is upstream of the jets 31, there is arrangedan electric heating element 33 which is connected to a non-illustratedsource of electric energy. A regulating flap or damper 34 is pivotallyarranged within the conduit 32 upstream of the heating element 33 andserves for directing the flow of air over the heating element. Anaerosol generator 35 of known construction is connected with the conduit32 via the branch pipes 36 and 37 which respectively communicate withthe conduit 32 upstream of the damper 34 and downstream of the heatingelement 33. The generator 35 is equipped with a knownaerosol-concentration controlling device 38. Neither the construction ofthe generator 35 nor that of the device 38 is of importance for thepurposes of the present invention.

The arrow S6 and the arrow S7 indicate the direction of flow of an aircurrent produced by the fan 27 and moving through the conduit 32; thedirection of the air current entering the aerosol generator 35 from theconduit 32, and reentering the conduit 32 from the aerosol generator 35,is indicated by the arrows S8 and S9, respectively.

If desired, a known device 39, connected to a source 40 of high voltage,may be arranged in the conduit 32 upstream of the aerosol inlet means 30for the purpose of charging the aerosol particles by means of coronadischarge.

The chamber 1 is provided with an external jacket or sleeve 41 to whichhot steam or other heat-exchanging fluid is supplied via conduit 42 andwithdrawn via a conduit 43. Inasmuch as steam is assumed to be theheatexchanging fluid in the illustrated embodiment of FIG. 1, a valve 44is provided for withdrawal of the condensate.

It will be seen that the construction of the chamber 1 and thearrangement of the feed mechanism 3 and the Withdrawal mechanism 5therewithin is such that the chamber 1 constitutes an integral housingwhich is closed with reference to ambient atmosphere.

In accordance with the invention the output rate of the feed mechanism3, and the withdrawal rate of the with drawal mechanism 5 are alike, sothat the quantity of new fibrous material supplied into the uppersection 2 of the housing 1, that is onto the uppermost surface of themass of fibrous material already contained in the housing 1, isidentical with the amount of fibers withdrawn from this mass at thelower section 4 by the with drawal mechanism 5.

The apparatus illustrated in FIG. 1 is particularly suitable for thedyeing of polyester staple fibers with a dispersion dyestulf aerosol.The polyester staple fibers 57 are continuously supplied from apreparatory spinning plant to the feed table 7. They are opened toflocks in the feed mechanism 3, and these flocks are then hurled intothe interior of the cylindrical chamber 1 where they are deposited ontothe homogeneous fibrous mass contained therewithin. Once the chamber 1has been filled to the level of the aerosol inlet means 30, thewithdrawal mechanism 5, and the fan 27 and aerosol generator 35 arestarted simultaneously. Withdrawal of fibrous material by thewithdrawing mechanism 5 results in downward movement of the mass 58 offibrous material in the chamber 1. Thus, the uppermost surface or layerof the mass 58 is continuously renewed by the addition of freshuntreated fibers thereto via the feed mechanism 3. This downwardmovement of the mass 58 is identified with the arrow S16.

The aerosol in form of a dispersion dyestutf is introduced into thechamber 1 via the aerosol inlet means 30. As a result to the suctioneffect produced by presence of sub-atmospheric pressure in the screencage the aerosol penetrates the mass 58 of fibrous material in thedirection of the arrow S17, that is in concurrent flow with thedirection of movement of the fibrous material 58. During this passagethrough the fibrous material, the aerosol particles adhere to thepolyester staple fibers 57 which make up the mass or body 58. Once theaerosol has passed through the mass 58, and has thus been substantiallyconsumed in the treating process, the remainder is sucked off in thedirection of the arrows S18 into the screen cage 15 and to the fan 27from where it is returned through the conduit 32 over the electricheating element 33 back to the inlet means 30 where it is combined ormixed with fresh aerosol. A portion of the substantially consumedaerosol aspirated into the screen cage 15, that is almost pure remainingair, in vented by means of the distributing flap 34 into the branch pipe36 and from there to the aerosol generator 35. There it is saturatedwith fresh aerosol, mixed with heated air, and supplied to the aerosolinlet means 30 for admission through the jets or nozzles 31 thereof intothe chamber 1. The electrical charge of the aerosol particles iseffected by means of the device 39, if such a device is provided.

The chamber 1 is preheated to a suitable dyeing temperature, so that,after the aerosol particles in form of a dispersion dyestuif areuniformly adhered to the polyester staple fibers 57 they are dissolvedon these fibers whereby the latter are colored. The concentration of theaerosol is adjusted by means of the device 38.

With this construction a perfect coloration of the polyester fibers isobtained during a single passage of the aerosol and of the fibersthrough the chamber 1 without necessitating the use of finishingprocesses, such as fixation, soaping, or washing or the like which arerequired in the previously known dyeing methods.

The apparatus illustrated in FIG. 2 is substantially similar to that ofFIG. 1. It also comprises a feed mechanism 3 corresponding to that shownin FIG. 1. The withdrawal mechanism 5a utilized in FIG. 2 comprises apair of knurled rollers 45 and -46 which are coupled for joint rotationby means of a transmission element 47 so that they can be drivensimultaneously by an electric motor 48. The arrows S10 and S11 indicatethe direction of rotation of the rollers 45 and 46. It will beappreciated that suitable arrangement must be provided for effectingthis oppositely directed rotation of the two rollers, but sucharrangements are well known to those skilled in the art. The rollers 45and 46 are arranged below a relatively narrow outlet opening 49 in thesection '4 of the chamber 1a, and downwardly of this outlet opening 49and of the rollers 45, 46 there is arranged a hopper feeder 50 whichsupplies fibers withdrawn by the rollers 45 and 46 and deposited in thehopper feeder 50 onto a conveyor belt 51 which is driven in thedirection indicated by the arrow S12 via a transmission element 52 andan electric motor 53.

Contrary to the embodiment of FIG. 1, the aerosol inlet means 30a inFIG. 2 is arranged in the section 4 of the chamber 1, that is in thelowermost part of the latter. The tubular ring provided with the outletjets or nozzles 31a is connected to a main conduit 54 which communicateswith the aerosol generator 35 and the fan 27, both of which areidentical with constructions shown in FIG. 1. The fan 27 in turn isconnected to a suction device consisting of a tubular ring 55 withnozzles 56, this ring being arranged in the uppermost section 2 of thechamber 1a.

The arrow S13 indicates the direction in which an air current moves fromthe ring 55 to the fan 27, and the direction of the air current from thefan 27 to the aerosol inlet means 30a is identified by arrow S14. ArrowsS8 and S7 respectively indicate the direction of an air current passingfrom the conduit 54 into the aerosol generator 35, and from the latterback into the conduit 54 downstream of the air current regulating flap34 installed in the conduit 54. To prevent the individual fibers frombeing entrained into the nozzles 31a and 56 of the aerosol inlet means30a and the tubular ring 55, respectively, the nozzles 31a and 56 arecovered with a fine tulle knitting (not illustrated). As in theembodiment of FIG. 1, the chamber 1a with the feed mechanism 3constitutes an integral closed housing. No heating element correspondingto the element 33 of FIG. 1 is provided.

The apparatus of FIG. 2 is particularly well suited for lubricating woolfibers 59 with an aerosol lubricating agent. In this embodiment theaerosol is caused to penetrate the layer or mass 58:: of wool fibers,which advances in the direction of the arrow S16, and this penetrationre sults from the presence of a sub-atmospheric pressure produced by thesuction device 55. As is clearly evident, the aerosol in this embodimentmoves countercurrent to the direction of advancement of the mass 58a, asindicated by the arrows S20 for the movement of aerosol, and the arrowsS16 for the movement of the fibrous mass 58a. During this relativemovement the lubricating agent adheres to the Wool fibers. Thesubstantially consumed aerosol is aspirated out of the chamber 1, in thedirection of the arrow S20, as already indicated and recirculatedthrough the main conduit 54, to the aerosol inlet means 30a. andtherefrom back into the chamber 1. A portion of the recirculated aerosolis introduced by means of the flap 34 into the branch pipe 36 and fromthere into the aerosol generator 35. Therein it is saturated with newaerosol and is then returned via the branch pipe 37 to the conduit 54and thence to the aerosol inlet means 30a. The aerosol concentration isagain determined by the aerosol concentration controlling device 38.

The wool fibers lubricated in the embodiment of FIG. 2 are withdrawn atthe outlet 49 by the rollers 45 and 46 and are supplied by these rollersinto the hopper feeder 50 from where they drop onto the conveyor belt 51which supplies them to another processing station. The treatment in thisembodiment proceeds at room temperature and results in uniform andeconomic lubrication of the wool fibers.

It is to be noted that the dispersed phase of the aerosols which are tobe used in accordance with the present invention may be solid, liquid ormixed. Aerosols having solid particles dispersed therein may be used,for instance, in processes for optically brightening or dyeing syntheticfibers. Liquid aerosols may be used for lubricating, condition,graphiting or other ways of treating natural or manmade fibers. Aerosolblends comprising solid particles of a dispersion dyestuff and liquidaqueous particles may be used for various different purposes, e.g. forthe dyeing of synthetic fibers.

As already indicated the present invention will be carried out at roomtemperature (embodiment of FIG. 2) or at elevated temperatures(embodiment of FIG. 1). The room temperature processing is preferable incertain circumstances, for example, when liquid aerosols are to be used.Elevated temperatures, on the other hand, are particularly advantageousif solid-particle aerosols are employed or in cases where the aerosolparticles are to be dissolved on the fibers or into the fibers afterhaving been deposited thereon, or are intended to enter into a chemicalreaction with the fibers.

As also clear from the preceding disclosure, the method according to thepresent invention may be performed at atmospheric pressure, atsub-atmospheric pressure or at super-atmospheric pressure.Sub-atmospheric and superatmospheric pressure may be used, for example,for the purpose of accelerating the dissolution of the aerosol particlesin fibers, or for accelerating or retarding a chemical reaction betweenthe fibers and the aerosol particles adhered thereto.

Separability of the aerosol particles within the layer or mass offibrous material is further enhanced if the aerosol particles and/or thefibrous material to be treated are provided with an electric changewhich may be either unipolar, or bipolar. It is preferred that if theaerosol particles are so charged, they be provided with a unipolarcharge because this contributes to an increase of the separability ordistribution of these particles. Charging of the aerosol particles canbe effected by means of corona discharge, by ultra-violet irradiation,from a radioactive source or the like. All of this is known and ismentioned here only for purposes of complete description. On the otherhand, the fibrous material can be charged by moving it in anelectrostatic field between elcetrodes of a capacitor connected to ahigh voltage source. Because of difierent dielectric constants of theaerosol vehicle and the fibrous material to be treated, the strength ofthe electrostatic field increases in the direction towards the fibers.The particles bearing the opposite charge, as well as the unchargedparticles, are attracted to the fibers in the direction of increasinggradient of the electrostatic field. In separating actions caused byelectrostatically charged mechanisms natural charges of the aerosolparticles can be utilized. Again, this is mentioned here not as a basicconcept of the invention, but only for the sake of completeness, suchexpedients already being known in the art.

It will be understood that each of the elements described above, or twoor more together may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in amethod and apparatus for treating fibrous materials with aerosols, it isnot intended to be limited to the details shown, since variousmodifications and structural changes may be made without departing inany way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting features thatfrom the standpoint of prior art clearly constitute essentialcharaceristics of the generic or specific aspects of this invention andtherefore, such adaptations should and are intended to be comprehendedwithin the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:

1. A method of treating fibrous materials with aerosols in an enclosedspace having an upper and a lower portion, comprising the steps ofintroducing into said upper portion of said enclosed space tufts offibrous material for gravity descent to said lower portion, to therebyprovide in said enclosed space a layer of said fibrous material havingan upper and a lower side and a thickness smaller than the height ofsaid enclosed space; continuously introducing first quantities ofadditional tufts of said fibrous material into said upper portion ofsaid enclosed space for gravity descent onto said upper side of saidlayer, and continuously withdrawing from said lower side of said layersecond quantities of fibrous material substantially identical to saidfirst quantities, so that said layer is continuously renewed as a resultof gravity descent of said first quantities from said upper side to saidlower side of said layer; and continuously passing through the thusconstantly renewed layer of fibrous material an aerosol in predetermineddirection from one to the other of said sides so as to effect filtrationof said aerosol through said layer to thereby treat the fibers of saidlayer with said aerosol.

2. A method as defined in claim 1; and further comprising the step ofmaintaining atmospheric pressure at said one side and sub-atmosphericpressure at said other side.

'3. A method as defined in claim 1; and further comprising the step ofmaintaining super-atmospheric pressure at said one side and at mostatmospheric pressure at said other side.

4. A method as defined in claim 1, wherein said aerosol is passedthrough said layer in predetermined direction from said upper to saidlower side.

5. A method as defined in claim 1, wherein said aerosol is passedthrough said layer in predetermined direction from said lower to saidupper side.

6. A method as defined in claim 1, the step of passing an aerosolthrough said mass comprising ejecting the aerosol from an aerosolgenerator; and further comprising the step of withdrawing the spentgaseous phase of the aerosol from said space at said other side, andrecirculating at least some of the spent gaseous phase to said aerosolgenerator.

7. Apparatus for treating fibrous materials with aerosols, comprising,in combination, confining means defining an enclosed space having anupper and a lower portion, for confining a layer of fibrous materialwhich tends to descend under the influence of gravity from said upperportion to said lower portion; feed means for continuously introducinginto said upper portion first quantities of tufts of fibrous materialfor gravity descent onto an upper side of said layer; withdrawing meansfor continuously withdrawing from a lower side of said layer secondquantities of fibrous material which are substantially identical to saidfirst quantities, so that said layer is continuously renewed as a resultof gravity descent of said first quantities from said upper side to saidlower side of said layer; and treating means for continuously passing anaerosol through said layer from one to the other of said sides thereof,so as to effect filtration of said aerosol through said layer to therebytreat the fibers of said layer with said aerosol.

8. Apparatus as defined in claim 7, wherein said confining meanscomprises wall means defining a substantially vertical chamber.

9. Apparatus as defined in claim 8, wherein said chamber is of hollowcylindrical configuration.

10. Apparatus as defined in claim 8, wherein said treating meanscomprises supply means communicating with said upper portion foradvancement of the aerosol in direction to said lower portionconcurrently With the movement of said fibrous material.

11. Apparatus as defined in claim 10; and further comprisingsuction-producing means communicating with said enclosed space at saidlower portion thereof for facilitating advancement of said aerosolthrough said layer of fibrous material, and for removing from saidenclosed space such aerosol which penetrates through said layer offibrous material to said lower portion.

12. Apparatus as defined in claim 8, wherein said treating meanscomprises supply means communicating with said lower portion foradvancement of the aerosol in direction to said upper portioncountercurrent to the movement of said fibrous material through saidchamber.

13. Apparatus as defined in claim 12; and further comprisingsuction-producing means communicating with said enclosed space at saidupper portion thereof for facilitating advancement of said aerosolthrough said layer of fibrous material, and for removing from saidenclosed space such. aerosol which penetrates through said layer offibrous material.

E14. Apparatus as defined in claim 8, said treating means comprisingaerosol supply means communicating with said upper portion forintroducing said aerosol into said enclosed space and suction-producingmeans communicating with said enclosed space at said lower portion forremoving residual aerosol from said enclosed space.

15. Apparatus as defined in claim 14; and further comprising returningmeans for returning the residual aerosol to said aerosol supply means.

References Cited UNITED STATES PATENTS 2,089,992 8/1937 Campbell et al-68-5X 3,175,375 3/1965 Yazawa et al. 68-5 WILLIAM 1. PRICE, PrimaryExaminer A US. Cl. X.R.

